My Compression Technique: Good But Not Good Enough

Hi! I've been working on several compression techniques, both open-source and closed-source, and am making good process. However, I am not doing as well as I like. The open-source version is based on the ZX0 technique, which can be found ="https://github.com/einar-saukas/ZX0"]here. I added to it Adaptive Huffman Codes, my own way to handle lengths, Last16, methods to not use LZ77 if it will result in worse compression than Huffman and a way to not compress a value using Huffman if it will be >=8 bits long. Last16 is a way to shorten a repeated LZ77 block to an offset to the previous block. I'm asking if there's anything else I can add to it.